Joint angle and delay estimation (JADE) for signals in multipath environments

We propose a subspace-based approach to estimate the angles-of-arrival (AOAs) and delays of multipath signals from one or more digitally modulated sources arriving at an antenna array. Our approach uses a collection of estimates of a consistent space-time vector channel. The channel estimates from different time slots in TDMA systems have constant path AOA and delay over the observed periods, but variable fade amplitudes between the slots. With this approach, we are able to estimate more parameters than the number of antennas. The Cramer-Rao bound for the parameter estimates is also provided.